Segregation Behavior of Impurity Iron in Primary Silicon During Directional Solidification of a Hypereutectic Silicon–Titanium Alloy

Iron (Fe) in metallurgical-grade silicon (MG-Si) is the main metal impurity and difficult to remove. Strengthening segregation of Fe at solid–liquid interface key purifying MG-Si; therefore, a refinement method for directional solidification hypereutectic silicon–titanium (Si–Ti) alloy was proposed, ability quantified by calculating equilibrium coefficient Fe. By analyzing microstructure, thermodynamics, Si-rich layer, it confirmed that during Si–Ti refining stronger than MG-Si. The results showed phases containing precipitates layer included τ5 τ1 phases. After introducing Ti into Si melt, impurities significantly reduced, Si–10 wt pct Ti–0.396 k0Fe = 8.68 × 10−7, which much lower MG-Si (6.4 10−6). During Fe, removal rate increased from 90.5 96.75 99.86 pct. This work helps provide understanding behavior alloys lays theoretical foundation deep impurities.